#include<iostream>
#include<vector>
#include<string>
#include<algorithm>
using namespace std;

/**
 * // This is the interface that allows for creating nested lists.
 * // You should not implement it, or speculate about its implementation
 * 
 * 
 * */
 class NestedInteger {
 public:
      // Return true if this NestedInteger holds a single integer, rather than a nested list.
      bool isInteger() const;
 
      // Return the single integer that this NestedInteger holds, if it holds a single integer
      // The result is undefined if this NestedInteger holds a nested list
      int getInteger() const;
 
      // Return the nested list that this NestedInteger holds, if it holds a nested list
      // The result is undefined if this NestedInteger holds a single integer
      const vector<NestedInteger> &getList() const;
  };
 
class NestedIterator {
public:
    NestedIterator(vector<NestedInteger> &nestedList) {
        funx(nestedList,0);
    }
    
    int next() {
        if(hasNext()){
            return V[i++];
            
        }
        return 0;
    }
    
    bool hasNext() {
        if(i<V.size()){
            return true;
        }
        else{
            return false;
        }
    }

    void funx(const vector<NestedInteger>& nestedList,int index){
        if(index==nestedList.size()){
            return;
        }
        if(nestedList[index].isInteger()){
            V.push_back(nestedList[index].getInteger());
            funx(nestedList,index+1);
        }
        else{
            funx(nestedList[index].getList(),0);
            funx(nestedList,index+1);
        }
    }

public:
    vector<int> V;
    int i=0; 
};

/**
 * Your NestedIterator object will be instantiated and called as such:
 * NestedIterator i(nestedList);
 * while (i.hasNext()) cout << i.next();
 */